Have you ever wondered what happens when a C program is compiled and executed on a system? This class will investigate the life of a binary from birth as C source code to death as a process running in memory being terminated.
Topics will include but are not limited to:
• Scanning and tokenizing source code.
• Parsing a grammar and outputting assembly code.
• Different targets for x86 assembly object files generation. (E.g. relocatable vs. position independent code).
• Linking object files together to create a well-formed binary.
• Detailed description of the Windows PE binary formats.
• How Windows loads a binary into memory and links it on the fly before executing it.
Along the way we will discuss the relevance of security at different stages of a binary’s life, from how viruses *really* work, to the way which malware “packers” duplicate OS process execution functionality, to the benefit of a security-enhanced OS loader which implements address space layout randomization (ASLR).
Lab work will include:
• Manipulating compiler options to change the type of assembly which is output
• Manipulating linker options to change the structure of binary formats
• Reading and understanding PE files with PEView
• Using WinDbg to watch the loader resolve imports in an executable
• Using Thread Local Storage (TLS) to obfuscate control flow and serve as a basic anti-debug mechanism
• Creating a simple example virus for PE
• Analyze the changes made to the binary format when a file is packed with UPX
• Using the rootkit technique of Import Address Table (IAT) hooking to subvert the integrity of a program’s calls to external libraries, allowing processes to be hidden.
The prerequisites for this class are a basic understanding of C programming and compilation. This class will be recommended for a later class on rootkits, and required for a later class on malware analysis.